


Sanity Break

by DavidB1000



Category: Supergirl (TV 2015)
Genre: Dark, Evil Lena Luthor, F/F, Graphic Depiction of Violence will come, I Will Go Down With This Ship, Lena Luthor Knows Kara Danvers Is Supergirl, Lena is Sneaky, No Really I Will, Plot Twists, Poor Kara, Violence
Language: English
Status: In-Progress
Published: 2017-12-08
Updated: 2017-12-09
Packaged: 2019-02-12 04:53:21
Rating: Mature
Warnings: Graphic Depictions Of Violence
Chapters: 2
Words: 4,040
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12951711
Author URL: https://archiveofourown.org/users/DavidB1000/pseuds/DavidB1000
Summary: Supergirl stops being a nice guy, which ends badly for a lot of people. What made her this way? Lena "died".However, things are most certainly not as they seem, as Kara will soon come to see.





	1. Kneel

Kara stormed into the DEO headquarters from the balcony and ignoring everyone's looks, walked towards Alex's lab.  
Alex looked up as Kara walked in. “Hey, Kara.” 

“I don't want to be a good guy anymore.” Kara frowned.  
Alex chuckled. “You stopped a lot of crime in the city. Please don't add to it.”  
“Haha. No, I'm serious. It's ridiculous.” Kara sighed.

“I know you're upset Lena was hurt a few days ago.” Alex frowned.  
“She wasn't just hurt, I know it was Morgan Edge. I know it!” Kara growled.

“I understand, but Lena herself even told you to let her recover, before you did anything rash.” Alex spoke.

Kara sighed. “Okay. You're right.” 

&^&

“Lena?” Kara spoke and knocked on Lena's balcony door.  
Lena looked up from the couch and gestured for Kara to come in.  
Kara did so and walked over to Lena and hugged her. Then she kissed Lena.  
“I am so sorry we still have to be secret.” 

Lena smiled. “It's okay.”  
Kara sighed. “I just, it's like I said to Alex earlier, I don't want to be a good guy anymore.”  
Lena chuckled. “Honey, while I would be with you, and help you, no matter what, I would be the only person to do so.” 

“Couldn't you find a way to make me immune to Kryptonite?” Kara sighed.  
“Sure, with a lot of effort. I know you don't want to do anything rash.” Lena smiled. “Tell you what, I will help you through everything, no matter what.”  
“Thank you, Lena.”

&^&

Three days later...

Alex knew it was going to be a bad day when Winn rushed into her office, his face pale as a ghost. “Alex. Lena...there was an explosion at L-Corp. We know Lena was there, because she was talking to Kara at the time, and the line died, and Kara is not here anymore.” 

Alex winced. “I know what's going to happen.” 

&^&

Morgan Edge looked up from his scotch as his office doors exploded into many pieces and Supergirl walked through.  
He sighed. “Those were like $5000. I liked them!” 

“Who cares. You killed Lena, now I'm going to remove your spleen and make you eat it!” Kara growled.  
“I don't think a spleen tastes good. Look, If I was going to kill Lena, wouldn't you think I'd make sure you weren't even on the planet first? I'm not an idiot.” Morgan Edge sighed.

“Yes, you are.” Kara growled and walked over to him and lifted him off the ground and into the air with one hand.  
“Now, I said before that I am through being a good person. So, Morgan, you are going to be the first person I kill.” Kara growled.

Morgan Edge winced. “Before you kill me, at least let me have a final drink of my scotch I was drinking. It's really good, and it's expensive, and you don't strike me as a scotch drinker.” 

Kara smirked and dropped him. He stumbled back up and then slowly drank his scotch.  
“I'll be honest, I prefer the taste of Cognac.” Kara sighed. “Or barring that, Antifreeze.”

Morgan Edge chuckled. “Antifreeze? You are full of surprises.”  
Alex rushed into the room a moment later. “Kara. Don't do this.”  
Kara sighed and looked over at Morgan finishing the last bit of his scotch. “He made peace, you need to now, Alex, with what I'm doing.”  
With a lightning fast movement, Kara snapped Morgan Edge's neck. To Alex, it looked as though, one moment he was fine, and the next his head was on backwards and he hit the floor hard.  
Alex winced. “Kara....please.” 

She could possibly handle Kara now, with kindness.  
Everything that would happen would depend on how she spoke. Kara could kill her in an instant if she wanted. 

“Kara. Please. I know you are hurting that Lena died. I'm simply asking you to not go any further.”  
“I'm through being a good guy, Alex.” Kara frowned. “I made up my mind. It's too damn frustrating. I thought I could be a good guy. I thought being a hero was a great thing. I loved saving people. But I have so many things I can't do because I'm a good guy, and I am tired of letting others suffer. I loved Lena. We were together in secret, because we didn't want anyone to know.”

Alex took a deep breath. “I didn't know, Kara. I'm sorry.”

“I know, and it's just, I know it's bad to kill people. I know that, but I'm sorry, Alex, I can't be a good guy anymore.”  
“You can still be like Bane!” Alex spoke.

Kara chuckled. “I am aware that after Bane got off Venom he followed in Batman's footsteps.”

Alex sighed. “Please, Kara, you can still help people.”  
“No, Alex, I'm sorry, it's past that point. I can't be good any more. My light is gone. Lena is dead.” Kara sighed.

“I can convince Sara to take me back in time and rescue Lena.” Alex spoke.

“No, no, there's no reason to travel back in time for this. Let me be myself, Alex. You can't stop me now, you know that. You don't have any Kryptonite on you. Your heart is beating erratic beyond measure. It would be calm if you had Kryptonite on you.”

“Kara, you're so damn smart, and I would never hurt you. If you have to be dark now, I understand, but please, don't kill innocent people.”Alex frowned.

“I won't.” Kara sighed and rushed out the window.

&^&

Kara stood on top of CatCo, looking out into the darkness. The sun had set a few hours ago. She sighed happily, and then turned, and grabbed a figure out of the darkness.  
“I'm not here to hurt you, Kara.” The man spoke calmly.  
Kara sighed. “What do you even want, Bruce.” 

“I know you're not a bad person at heart, Kara.” Batman spoke.

“My love is dead. I can't be a good guy anymore, and let's face it, you're not Happy Mcjoyful towards any bad people. Well, maybe Catwoman.” Kara grinned.  
“Regardless of Catwoman and I, you're hurting, I understand that.” Batman spoke.

“You lost your family when you were 8, I lost my planet when I was 13. I saw it explode! Superman didn't. There is no comparison here. I lost Lena because I dared to let me guard down. That stops now. If I have to be the type of person to kill, I will. I will simply not let myself be hurt again.” Kara sighed.

“And it would be Hypocritical of me in the extreme to lecture anyone about killing people.” Batman sighed. “But you know you can't expect people to be happy with your choices.” 

“I understand that, Bruce. I don't care though. I just want to be me. I'm through being nice. It ended horribly for Lena. I won't let kindness get in my way again.” Kara sighed. “If people think I'm a monster because of it, that's fine. I don't care anymore.” 

“You're extremely strong willed, in many ways you're more suited to killing others than all the villains I've faced.” Batman sighed.  
Kara looked at her hands. “The biggest problem, Bruce, is I honestly don't want to care anymore. The love of my life died. You had 8 years with your parents. Superman would have loved to have 8 years with his parents on Krypton, I had 13, and I still miss them. Every day. I just honestly can't care any more about kindness, niceness, compassion, or what people expect.” 

“That is why I just want you to know, I won't go after you. It would be suicide on my part, and everyone thinks I can beat Superman with my eyes closed while on fire wearing nothing but underwear coated in Caspasian..” Batman sighed.

Kara chuckled. “Of all things, people fail to realize how smart you are. You know you're dead if Superman really wanted to kill you.” 

“By any human frame of reference, it would be instant.” Batman sighed. “I just want you to know, that no matter what happens, I am not against you. I can't be against you. All the Kryptonite in existence won't stop you from killing me. I know that.” 

Kara nodded. “Exactly. Thank you for being understanding.”

&^&

2 days later...

The bank robbers screamed as Kara threw them around the bank with great force.  
“My leg!” One of them screamed as he landed wrong.  
Kara chuckled. “Sorry, gentlemen, it's time to kick ass and take names.” 

“You're supposed to be a good guy!” One of the bank robbers yelled.

“You must have not got the memo.” Kara sighed and grabbed the nearest bank robber. “You see, I stopped being a good guy when my girlfriend was murdered!” 

“You're gay?” The bank robber blinked.  
“Pansexual, but that's not a discussion I'm having with you.” Kara sighed, and twisted the man's neck around.  
He collapsed dead and she walked up to the remaining bank robbers, frozen in shock.  
Their screams echoed outside.

“Jesus, Mary, and Joesph.” Detective Maggie Sawyer yelled as she walked into the room to see the carnage.  
Kara wiped off some blood on her costume, and sighed. “Did no one get the memo? I'm not a good guy anymore.” She walked by Maggie, ignoring her.

“Kara! Wait, I know Alex and I broke up, but I will always be here for you if you need it.” Maggie spoke.

“That's nice, but no thanks for right now.” Kara said and left.

&^&

Kara landed a short time later at her apartment, and sighed. She would take a shower, probably cry a bit, and then go out to patrol the city for more criminals to remove. At least that was her plan, until she walked into her apartment and groaned as she saw someone sitting on her couch.

“What the hell do you want?” Kara groaned.  
The woman smiled. “I heard that you went a bit dark after Lena died.”  
Kara groaned. “I'm not in the mood for this shit, Lillian.” 

“I know. I've just come to give you something that will help you reap a path of bloody vengeance.” Lillian sighed.

“What?” Kara asked, bored of the conversation.  
“Immunity to Kryptonite.” Lillian stated simply. 

“You have my undivided intention.” Kara grinned.  
Lillian took out a vial of a blue liquid. “This is the culmination of my knowledge and research on Kryptonians. This will completely render you immune to the effects of Kryptonite, and it's easier than you going and sitting inside the sun for 100 years.”

“Good point there, Lillian. But if you are trying to trick me, I will hit you so hard, you will fly backwards in time and kill your past self.” Kara growled.

“Believe me, I do not wish to incur your wrath after Lena died.” Lillian sighed.

Kara nodded. “Good point.”  
She took the vial and drank it it. “Well, that could have tasted better.” She grimaced. “How will I know it works?” 

Lillian smirked. “That shouldn't be too hard for you.”

&^&

Alex nearly had a heart attack when she woke up in her apartment to see Kara standing by her bed.  
“AHHHHH! Geez, Kara!” Alex groaned.

Kara grinned and turned on the light. Alex winced, and then her eyes recovered and she saw Kara holding a green rock in her hand. “Why are you holding Kryptonite?”  
“Because it does nothing now! Thanks to Lillian.” Kara smirked.

“Great.” Alex groaned.  
“Regardless, I will hurt no good guys as long as they do not attack me first. Make sure everyone knows that.” 

&^&

The next day Kara was standing on the roof of CatCo when someone landed behind her on it. She turned and grinned. “Well, now, Diana, I hope like Bruce you understand how strong I am.”  
Wonder Woman sighed. “I do not want to ever fight you, Kara. I just, I am disappointed in you.” 

“Yeah, well, join the club. I won't hurt anyone as long as they don't try to stop me from dispensing justice in my city.” Kara grumbled.

“Is it justice to murder people for robbing a bank?” Wonder Woman spoke.

Kara sighed. “I'm sorry, but I can't afford to be nice any more. My heart is dead.”  
“What if there was a way to get Lena back?” Wonder Woman asked.

“I already said to Alex, I don't want time travel. I don't want to take the super easy way out.” Kara sighed.  
“What if you don't need time travel?” Wonder Woman asked.

Kara sighed. “I'm sorry. I just, I need to be me now. I can't concern myself with anything else.”  
Wonder Woman sighed. “I'm worried about you, Kara.”

“I'm not going to go full dark yet. You know Superman beat you in every fight you had with him. You know I can too.” Kara frowned and looked Wonder Woman dead in her eyes. “Please, leave me be.” 

Wonder Woman frowned. “Alright, Kara. For now.” 

&^&

“This was not how I expected things to go, Roulette.” Detective Maggie Sawyer sighed as she sat down at the large table with several other people.  
“It's like the old adage, always expect the unexpected, dear.” Veronica Sinclair, A.K.A. Roulette chuckled.  
The third woman of the group sighed. “I've said it before, and I'll say it again, my plan will work. My mother helped Kara out with the Kryptonite problem. Now all we got to do is wait for the right time, and Kara will be the person she was always meant to be.”  
The only man in the group sighed, the light in the room reflecting off his bald head. “Not to be a downer on all this, but, Lena, are you sure you accounted for every variable here?”  
“Believe me, Lex, I'm not an idiot.” Lena Luthor chuckled.


	2. Bottom Line

**Summary for the Chapter:**

> More is revealed and Kara is reunited with Lena!

“You're not supposed to be like this, you know that.” The voice distracted Kara from her thoughts as she stood on the roof the DEO.  
Kara turned and looked at Irma. “What the hell do you want?” 

“Mon-El, me, we're not your enemies. Neither are your friends.” Irma frowned.

“I really don't care what you want to say to me, Irma.” Kara sighed.  
“I know you're hurting from the loss, but you can't think this is what Lena would want.” Irma spoke softly.

Kara flinched and walked over to Irma. She picked her up by her throat. Irma's eyes widened. “PUT ME DOWN!” The words screamed in Kara's head and she reeled backwards as if struck.   
She dropped Irma and groaned. “You're Psychic!?”  
Irma rubbed her sore throat. “Damnit, I wasn't trying to hurt you, Kara. We just need you to see you're doing things wrong. You need to just relax.” 

Kara shook her head. “I'm not going to relax. There's still evil out there. I can't stop all of it but I can stop most of it” 

“Kara, please, wait, let me talk to you.” Irma frowned.

“Believe me, you've done enough, and I hate psychics.” Kara growled.

“I'm not the bad person here.” Irma said, and reached out her hand.   
Kara glared at her and then turned away. “Please, Kara, let me talk to you.” 

Kara took a deep breath, curled her left hand up into a fist, and swung it, stopping an inch away from Irma's forehead. She extended a finger. “Let's see you psychic your way out of this.” 

Her finger lightly touched Irma's forehead, from a distance it looked like it was traveling at a normal speed.   
Irma's eyes widened as she felt the effect of what Kara did and she stumbled backwards away from Kara and dropped to her knees. She gasped. “Time?” Her eyes widened even more and Kara chuckled. “Well, I meant to block your psychic ability. Looks like not the best time for a stroke. Enjoy the Aphasia.” Kara then turned around and flew into the air.

&^&

“Thyme Dime Hot Cold HELP!” Irma screamed.   
Alex winced. She wasn't exactly prepared to deal with a stroke at the DEO headquarters. Especially one caused by Kara. She was not happy with Kara slowly going down the path towards darkness.

Mon-El frowned. “This is not good, Alex. She's not the type of person to attack anyone, even Irma.”  
“I know, damnit. We've got a way to track her.”

A short time later, Mon-El was standing behind Winn and looking at a satellite live-feed of National City. “See, there's Kara. She's not hiding, so she knows she did something bad.” Winn spoke, relaxed.  
There was a quick and rapid blur of movement, and then the satellite feed cut out.   
Winn frowned. “I think she just punched out the satellite.” 

“Yeah, this isn't good.” Mon-El groaned.

“Do you think maybe Irma kind of hurt Kara?” Winn frowned.

“I can't imagine she would ever hurt Kara.” Mon-El spoke.

Alex walked out of the elevator from the medical floor she had been treating Irma in.   
“Good news?” Mon-El asked.

Alex looked at the ground. “Without knowing how exactly Kara scrambled her brain, I can't even attempt to fix the damage. Her Aphasia is wearing off at least. So at least Kara didn't scramble her brain that hard. Also, Irma keeps screaming that she's Psychic, and I know that's not from the Aphasia, because I keep hearing it in my head.” 

Mon-El sighed. “Yeah, She's a powerful psychic. She just knows how to control herself. The only way she'd reveal herself to Kara is if Kara tried to hurt her.”

“I'm not sure, Mon-El, but we may have to face the fact that Kara is no longer going to be Kara.” Alex frowned.

“Well, we're hosed then.” Winn groaned.  
“Very. Kara's immune to Kryptonite now.” Alex sighed.

“Oh, that's a wonderful thing to not tell us, Alex!” Winn groaned.

Alex sighed. “She showed up at my apartment the other day, and she was holding Kryptonite. She said Lillian Luthor gave the immunity to Kryptonite to her.”

“So, immune to Kryptonite, ready to kill a psychic, and basically not in a good mood.” Mon-El sighed.   
A voice spoke. “Sounds like Superboy Prime to me.” 

They turned to see Superman standing by them as if he had always been there.   
“Superboy Prime, really?” Mon-El frowned.   
Alex groaned and rubbed her forehead. “Kara hasn't gone fully off the deep end and accidentally punched a woman's face hard enough to make it explode.”   
“Who names these villains, Superman?” Winn sighed.

“At this point, I have given up understand the naming conventions of my villains. Long story short, Winn, he's an insane evil version of myself from another universe who lost his sanity after accidentally killing someone. And he has yet to recover. He also hits like a truck, and makes Doomsday feel about as weak as a newborn kitten.” Superman sighed.

“Great, he makes the dude who 'killed' you, and I am using quotes, look weak.” Winn groaned.

“Why can't my life be less complicated?” Alex asked.

“Against stupidity, the Gods themselves contend in vain?” Winn asked.  
“Not entirely, Winn.” Superman chuckled.

&^&

Kara stood watching the DEO, frowning, wishing she could see through lead without killing everyone inside from lethal radiation poisoning. “I think the time-table has moved up to the point where we need to talk.” 

Kara frowned and turned to see Maggie standing on the roof behind her. “There's no way on this roof without being me.”   
“I know people.” Maggie grinned. “But yeah, I think the time-table has changed, and we need to talk. It's about Lena.” 

“Okay, you have my attention.” Kara frowned.

“It's good news.” Maggie spoke.   
“How good?”  
“She's not dead.” Maggie smiled.

“That is wonderful!” Kara smiled.   
“Yes. Come with me, we need to have a talk with her.” Maggie spoke.

&^&

“This is a bit earlier than I had anticipated, but you nearly went dark before you should have.” Kara looked up and saw Lena walk down a flight of stairs.

Maggie had brought her to this location.  
Lena walked over to Kara and Kara frowned. “I thought you died, and it hurt me so much. I didn't mean to hurt Irma. I just, I'm not bad.”

“Shh, honey. It's okay.” Lena kissed Kara. “I know you didn't mean to do that. It's just for us to be together, I needed you ready to do what was necessary for me, and I'm sorry that I did it this way.”  
Kara sighed. “I only killed bad people.”   
“I know, and I'm so glad you did that. The only time good people need to be hurt is when they attack you.” Lena smiled.

“Exactly.” Kara relaxed a bit. “It's just, you did all this? You worried me so much.”   
“You'll understand in time why I did this. You and me, as always, versus the world. That's how it was meant to be.” Lena grinned.

“You're killing me here, Sis.” A man's voice spoke up, and Kara turned and her eyes widened. “Lex Luthor?! But you're in prison?” 

“Yes, because a prison that was built by humans could totally cage me.” Lex sighed.   
“Lex and I, Maggie, and Roulette have all been working together for quite some time, to get you prepared to do what needed to be done.” Lena spoke.

“What do you mean? What do I need to do?” Kara frowned.  
“You love me, right? You truly love me, right?” Lena asked.

Kara nodded. “Always. I told you, if you became the enemy of the world, I'd still be your knight in shining armor.”  
Lena smiled. “Exactly, and Kara, I love you, and I want you to be there with me. I don't want to rule the world. I just want to take care of all the bad people, and I know you can do that.” 

Kara smiled. “Exactly. For you, Lena, I would kill.”   
“I'm glad. You can start with my brother.” Lena grinned.

“What?! Lena, come on now, I was helping you out! You don't need to have me murdered!” Lex gulped.

As smart as he was, as resourceful as he was, he knew that he would be dead if Superman ever wanted to kill him. Kara here was truly capable of killing him in an instant, and it terrified him that his own sister truly became worse than he was. 

Lena chuckled. “Sorry, Lex, but you've always been a thorn in my side, even after you agreed to help me.”   
Maggie shrugged. “I have no feelings either way.” 

Kara smirked and walked over to Lex, who to his credit would not back up and flee. Lex may have been terrified, one of the only few times he ever was in his life, but he would face his death like a Luthor. 

Kara grinned and spoke. “I want you to know, Lex, it's really nothing personal. It's just business.”   
With that, she grabbed his head and twisted it on backwards.   
The sound of the neck breaking echoed through the room.   
Lex dropped dead and Lena sighed with relief. “Well, that's one problem solved. Kara, we need to go and talk, in private.”   
Maggie grinned. “Oh is that what we're calling it now?” 

“No, I mean literally, Maggie.” Lena grinned.

Maggie nodded and left.   
Lena turned to Kara, who had walked back over to her, and kissed her deeply. “I'm sorry, dear, I know you really don't like killing, even now.”   
Kara nodded. “I didn't feel anything for the people I killed until now, which is weird.”   
“I don't blame you for feeling something. As evil as Lex was, he was a lot different than the people you have killed before.” Lena grinned.

“He was related to you.” Kara spoke. “I understand, and I would kill even your family for you if you truly needed me to. And I know you would never want to conquer the world.” 

Lena nodded. “Exactly, dear. That's not my style. I only want to eliminate evil.”   
“I must say, the fact you used Morgan Edge's assassination attempt against you was clever.” Kara smiled.

“Oh, indeed. He needed to be killed though. That said, I think we should stop with the breaking necks. It's not strong enough to send a message to evil people.” 

Kara frowned. “Then what should I do?”   
“Punch them to death.” Lena smirked.

Kara chuckled. “Now that I can do.”

**Notes for the Chapter:**

> Aphasia is when you mix up words as you speak.  
> A stroke can do that.

**Author's Note:**

> Well now, who saw that twist coming at the end? :)  
> I mean, obviously because there was no Major Character Death tag, Lena didn't die. But still.  
> Hope you all like it.


End file.
